Unable to start Linux guest on 6.0.0

[McMagnus]

Have been running a Lubuntu guest on a Windows 7 host for 3+ years. After upgrading to VBox 6.0.0, I could start it once, then after upgrading the guest I was unable to restart it, the guest failed to boot probably because it failed to mount a disk. But after running recovery from within the guest, I was able to start it once. Then after shutting it down nicely for another upgrade, it fails to boot again, and now I can't even boot into recovery but get stuck in busybox with no disks mounted.

Plan to revert to VBox 5 soon if I can't get help here.

Log attached.

Edit: Also, always when shutting down WIndows now, it complains about being stuck on "Virtualbox interface, active connections"

[socratis]

Just to get one thing out of the way:

Plan to revert to VBox 5 soon if I can't get help here.

If you think you're going to get better help/advice if you revert to something older, the first advice in such a failure is always to update to the latest version. Unless it's a proven regression...

00:00:04.785741 Host RAM: 8089MB (7.8GB) total, 2770MB (2.7GB) available
00:00:09.080209 RamSize  <integer> = 0x0000000100000000 (4 294 967 296, 4 096 MB, 4.0 GB)
00:00:09.080571 VRamSize <integer> = 0x0000000008000000 (134 217 728, 128 MB)

You are assigning memory to your guest, that you do not have available. Either close some applications on the host, buy more RAM for the host, or reduce the amount of RAM assigned to the guest.

00:00:09.080204 NumCPUs <integer> = 0x0000000000000004 (4)
00:00:09.971082 CPUM: Physical host cores: 4

You have assigned all your CPUs to the VM. The host is going to run low on resources, since VirtualBox cares about physical processors (cores), not logical ones (threads).

[McMagnus]

Thanks for your reply.

I realize reverting would prohibit you from helping out, but if it works, I wouldn't need it and I can try the next v6 release.

In the past, setting too much RAM would show a very clear warning about it, I hope that's not gone?
And 4GB usually works fine, provided I start it first (which I probably didn't do in that log.)

And I have usually used all 8 logical CPUs for that VM. I'm pretty sure I have compared compilation times for the C++ project I'm developing on the guest, and it's a tad faster with 8 CPUs. Also, it's not as if the allocated CPUs are removed from the host, they just share them like any two processes.

Anyway, I decreased to 1GB RAM and 1 CPU with the same result, see log. Let me know if you want me to try something. You can throw almost anything my way if you want.

Edit: Reverted back to 5.2.22. Still didn't boot.
Restored a backup (boot and home VDIs), still didn't boot.
But now, I could start Linux in recovery. Made a dpkg repair and was able to start. But it only starts through recovery, not directly.
I was able to start directly using an old kernel (3.3)
I have now removed the two newer kernels (4.4.0-441 and 4.4.0-440) and it now starts every time.
Will now make a backup and try to upgrade kernel and then upgrade to VBox 6.0 again.


Edit2: In /lib/modules/4.4.0-140-generic/initrd/ there was an empty file called vboxvideo (or very similar). When I removed it, I am able to boot that kernel. Perhaps the circus started when I tried the new 6.0 setting to select emulated gfx?

Edit3: Same in VBox 6.0.0. If that empty file is present (vboxvideo), it won't boot, except through recovery. Even after installing guest additions 6.0.0.
Anyway, it's better now, I *can* boot. Before, I couldn't even get to recovery.

[socratis]

In the past, setting too much RAM would show a very clear warning about it, I hope that's not gone?

No, it's not gone, it still warns you, but based not on the available RAM (which can vary minute by minute), but based on the installed RAM. Not the same thing...

And 4GB usually works fine, provided I start it first (which I probably didn't do in that log.)

At the start or not, you got to keep an eye on your Task Manager at all times!

And I have usually used all 8 logical CPUs for that VM. ... Also, it's not as if the allocated CPUs are removed from the host, they just share them like any two processes.

Read the following. And notice Ramshankar's reply where he refers to physical, not even logical ones: viewtopic.php?f=35&t=77413

In /lib/modules/4.4.0-140-generic/initrd/ there was an empty file called vboxvideo (or very similar)

That's an interesting find...

Anyway, it's better now, I *can* boot

I'll leave the thread unmarked for the moment until we have a more solid understanding on what's going on.